Unsaturated cyclic anhydride end capped polyimides and polyamic acids and photosensitive compositions thereof

ABSTRACT

Embodiments in accordance with the present invention encompass polyamic acid or polyimide polymers containing a reactive unsaturated cyclic anhydride end group as well as photosensitive compositions made therefrom which are useful for forming films that can be patterned to create structures for microelectronic devices, microelectronic packaging, microelectromechanical systems, optoelectronic devices and displays. In some embodiments the compositions of this invention are shown to feature excellent hitherto unachievable mechanical properties. The negative images formed therefrom exhibit improved thermo-mechanical properties, among other property enhancements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/813,948, filed Mar. 5, 2019, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a series of unsaturated cyclicanhydride end capped polyamic acid and polyimide polymers. Morespecifically, the present invention relates to a photosensitivecomposition containing unsaturated cyclic anhydride, such as itaconicanhydride end capped polyamic acid and polyimide polymers. Thecompositions of this invention are useful for forming microelectronicand/or optoelectronic devices and assemblies thereof, and morespecifically, such compositions exhibit improved thermal, mechanical andopto-electronic properties.

Description of the Art

Organic polymer materials are increasingly being used in themicroelectronics and optoelectronics industries for a variety ofapplications. For example, the uses for such organic polymer materialsinclude permanent interlevel dielectrics, redistribution layers (RDL),stress buffer layers, chip stacking and/or bonding, leveling orplanarization layers, alpha-particle barriers, passivation layers, amongothers, in the fabrication of a variety of microelectronic andoptoelectronic devices. Where such organic polymer materials arephotosensitive, thus self-imageable, and therefore, offer additionaladvantage of reducing the number of processing steps required for theuse of such layers and structures made therefrom. Additionally, suchorganic polymer materials enable the direct adhesive bonding of devicesand device components to form various structures. Such devices includemicroelectromechanical systems (MEMS), microoptoelectromechanicalsystems (MOEMS) and the semiconductor device encompassing acomplementary metal oxide semiconductor (CMOS) image sensor damstructure, and the like.

There has been innumerable polymeric materials used in the art in orderto achieve the above noted desired requirements. One such class ofpolymers include polyimides and its precursor, polyamic acid. However,most of the polyimides disclosed in the art are generally for positivetone image forming films, and many not suitable for many applications.Some of the drawbacks include use of highly toxic and corrosive phenolicmonomers which provide alkali solubility that is required for formingpositive tone compositions. Other property disadvantages includeinsolubility of the polyimides and/or the precursor polyamic acids incommonly used solvents in the electronic industry, poor photo imagingcapabilities, among others. Even more importantly, such compositionssuffer from poor thermo-mechanical properties and may require high curetemperatures, often times higher than 300° C., which are undesirable.See for example, U.S. Pat. No. 8,946,852 B2 and U.S. Pat. No. 7,485,405B2.

Accordingly, it is an object of this invention to provide a series ofunsaturated cyclic anhydride end capped polyamic acid and polyimidepolymers and their compositions that provide improved thermo-mechanicalproperties.

It is also an object of this invention to provide compositions which canbe cured at lower temperatures than the conventional polyimides thatexhibit improved thermo-mechanical properties.

Other objects and further scope of the applicability of the presentinvention will become apparent from the detailed description thatfollows.

SUMMARY OF THE INVENTION

Surprisingly, it has now been found that incorporating unsaturatedcyclic anhydride, such as itaconic anhydride, as an end capped group forforming a series of polyamic acid and polyimide polymers as describedherein provides hitherto unattainable thermo-mechanical properties,among other property advantages. More specifically, the polyamic acidand polyimide polymers as disclosed herein can be made by employing anyof the known dianhydrides and diamines in combination with a substitutedunsaturated cyclic anhydride to produce unsaturated cyclic anhydridecapped polyamic acid or polyimide, which are soluble in commonly usedorganic solvents. The polymers of this invention can then be combinedwith a number of additives to form photosensitive compositions whichfeature excellent thermo-mechanical properties, photo-imagingproperties, low cure temperatures, generally below 250° C. or lower,among other property enhancements.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments in accordance with the present invention are described belowwith reference to the following accompanying figures and/or images.Where drawings are provided, it will be drawings which are simplifiedportions of various embodiments of this invention and are provided forillustrative purposes only.

FIGS. 1 to 3 show top down optical micrograph images of a compositionembodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the articles “a,” “an,” and “the” include pluralreferents unless otherwise expressly and unequivocally limited to onereferent.

Since all numbers, values and/or expressions referring to quantities ofingredients, reaction conditions, etc., used herein and in the claimsappended hereto, are subject to the various uncertainties of measurementencountered in obtaining such values, unless otherwise indicated, allare to be understood as modified in all instances by the term “about.”

Where a numerical range is disclosed herein such range is continuous,inclusive of both the minimum and maximum values of the range as well asevery value between such minimum and maximum values. Still further,where a range refers to integers, every integer between the minimum andmaximum values of such range is included. In addition, where multipleranges are provided to describe a feature or characteristic, such rangescan be combined. That is to say that, unless otherwise indicated, allranges disclosed herein are to be understood to encompass any and allsub-ranges subsumed therein. For example, a stated range of from “1 to10” should be considered to include any and all sub-ranges between theminimum value of 1 and the maximum value of 10. Exemplary sub-ranges ofthe range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8,and 5.5 to 10, etc.

As used herein, the expression “alkyl” means a saturated, straight-chainor branched-chain hydrocarbon substituent having the specified number ofcarbon atoms. Particular alkyl groups are methyl, ethyl, n-propyl,isopropyl, tert-butyl, and so on. Derived expressions such as “alkoxy”,“thioalkyl”, “alkoxyalkyl”, “hydroxyalkyl”, “alkylcarbonyl”,“alkoxycarbonylalkyl”, “alkoxycarbonyl”, “diphenylalkyl”, “phenylalkyl”,“phenylcarboxyalkyl” and “phenoxyalkyl” are to be construed accordingly.

As used herein, the expression “cycloalkyl” includes all of the knowncyclic groups.

Representative examples of “cycloalkyl” includes without any limitationcyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,cyclooctyl, and the like. Derived expressions such as “cycloalkoxy”,“cycloalkylalkyl”, “cycloalkylaryl”, “cycloalkylcarbonyl” are to beconstrued accordingly.

As used herein, the expression “perhaloalkyl” represents the alkyl, asdefined above, wherein all of the hydrogen atoms in said alkyl group arereplaced with halogen atoms selected from fluorine, chlorine, bromine oriodine. Illustrative examples include trifluoromethyl, trichloromethyl,tribromomethyl, triiodomethyl, pentafluoroethyl, pentachloroethyl,pentabromoethyl, pentaiodoethyl, and straight-chained or branchedheptafluoropropyl, heptachloropropyl, heptabromopropyl, nonafluorobutyl,nonachlorobutyl, undecafluoropentyl, undecachloropentyl,tridecafluorohexyl, tridecachlorohexyl, and the like. Derivedexpression, “perhaloalkoxy”, is to be construed accordingly. It shouldfurther be noted that certain of the alkyl groups as described herein,such as for example, “alkyl” may partially be fluorinated, that is, onlyportions of the hydrogen atoms in said alkyl group are replaced withfluorine atoms and shall be construed accordingly.

As used herein the expression “acyl” shall have the same meaning as“alkanoyl”, which can also be represented structurally as “R—CO—,” whereR is an “alkyl” as defined herein having the specified number of carbonatoms. Additionally, “alkylcarbonyl” shall mean same as “acyl” asdefined herein. Specifically, “(C₁-C₄)acyl” shall mean formyl, acetyl orethanoyl, propanoyl, n-butanoyl, etc. Derived expressions such as“acyloxy” and “acyloxyalkyl” are to be construed accordingly.

As used herein, the expression “aryl” means substituted or unsubstitutedphenyl or naphthyl. Specific examples of substituted phenyl or naphthylinclude o-, p-, m-tolyl, 1,2-, 1,3-, 1,4-xylyl, 1-methylnaphthyl,2-methylnaphthyl, etc. “Substituted phenyl” or “substituted naphthyl”also include any of the possible substituents as further defined hereinor one known in the art.

As used herein, the expression “arylalkyl” means that the aryl asdefined herein is further attached to alkyl as defined herein.Representative examples include benzyl, phenylethyl, 2-phenylpropyl,1-naphthylmethyl, 2-naphthylmethyl and the like.

As used herein, the expression “alkenyl” means a non-cyclic, straight orbranched hydrocarbon chain having the specified number of carbon atomsand containing at least one carbon-carbon double bond, and includesethenyl and straight-chained or branched propenyl, butenyl, pentenyl,hexenyl, and the like. Derived expression, “arylalkenyl” and fivemembered or six membered “heteroarylalkenyl” is to be construedaccordingly. Illustrative examples of such derived expressions includefuran-2-ethenyl, phenylethenyl, 4-methoxyphenylethenyl, and the like.

As used herein, the expression “heteroaryl” includes all of the knownheteroatom containing aromatic radicals. Representative 5-memberedheteroaryl radicals include furanyl, thienyl or thiophenyl, pyrrolyl,isopyrrolyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, isothiazolyl,and the like. Representative 6-membered heteroaryl radicals includepyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, and the likeradicals. Representative examples of bicyclic heteroaryl radicalsinclude, benzofuranyl, benzothiophenyl, indolyl, quinolinyl,isoquinolinyl, cinnolyl, benzimidazolyl, indazolyl, pyridofuranyl,pyridothienyl, and the like radicals.

As used herein, the expression “heterocycle” includes all of the knownreduced heteroatom containing cyclic radicals. Representative 5-memberedheterocycle radicals include tetrahydrofuranyl, tetrahydrothiophenyl,pyrrolidinyl, 2-thiazolinyl, tetrahydrothiazolyl, tetrahydrooxazolyl,and the like. Representative 6-membered heterocycle radicals includepiperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, and the like.Various other heterocycle radicals include, without limitation,aziridinyl, azepanyl, diazepanyl, diazabicyclo[2.2.1]hept-2-yl, andtriazocanyl, and the like.

“Halogen” or “halo” means chloro, fluoro, bromo, and iodo.

In a broad sense, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a few of the specificembodiments as disclosed herein, the term “substituted” meanssubstituted with one or more substituents independently selected fromthe group consisting of (C₁-C₆)alkyl, (C₂-C₆)alkenyl,(C₁-C₆)perfluoroalkyl, phenyl, hydroxy, —CO₂H, an ester, an amide,(C₁-C₆)alkoxy, (C₁-C₆)thioalkyl and (C₁-C₆)perfluoroalkoxy. However, anyof the other suitable substituents known to one skilled in the art canalso be used in these embodiments.

It should be noted that any atom with unsatisfied valences in the text,schemes, examples and tables herein is assumed to have the appropriatenumber of hydrogen atom(s) to satisfy such valences.

It will be understood that the terms “dielectric” and “insulating” areused interchangeably herein. Thus reference to an insulating material orlayer is inclusive of a dielectric material or layer and vice versa.

It will be understood that, as used herein, the phrase “microelectronicdevice” is inclusive of a “micro-optoelectronic device” and an“optoelectronic device”. Thus, reference to microelectronic devices or amicroelectronic device assemblies are inclusive of optoelectronicdevices and micro-optoelectronic devices as well as assemblies thereof.

It will be understood that the term “redistribution layer (RDL)” refersto an electrical signal routing insulation material which featuresdesirable and reliable properties. The term RDL may also be usedinterchangeably to describe buffer coating layers, such as for example,a stress relief or buffer layer between the solder ball and fragilelow-K structure.

As used herein, the terms “polymer composition,” “copolymercomposition,” “terpolymer composition” or “tetrapolymer composition” areused herein interchangeably and are meant to include at least onesynthesized polymer, copolymer, terpolymer or tetrapolymer, as well asresidues from initiators, solvents or other elements attendant to thesynthesis of such polymers, where such residues are understood as notnecessarily being covalently incorporated thereto. But some catalysts orinitiators may sometimes be covalently bound to a part of the polymericchain either at the beginning and/or end of the polymeric chain. Suchresidues and other elements considered as part of the “polymer” or“polymer composition” are typically mixed or co-mingled with the polymersuch that they tend to remain therewith when it is transferred betweenvessels or between solvent or dispersion media. A polymer compositioncan also include materials added after synthesis of the polymer toprovide or modify specific properties of such composition. Suchmaterials include, but are not limited to solvent(s), antioxidant(s),photoinitiator(s), sensitizers and other materials as will be discussedmore fully below.

As used herein, the term “modulus” is understood to mean the ratio ofstress to strain and unless otherwise indicated, refers to the Young'sModulus or Tensile Modulus measured in the linear elastic region of thestress-strain curve. Modulus values are generally measured in accordancewith ASTM method DI708-95. Films having a low modulus are understood toalso have low internal stress.

The term “photodefinable” refers to the characteristic of a material orcomposition of materials, such as a polymer or polymer composition inaccordance with embodiments of the present invention, to be formed into,in and of itself, a patterned layer or a structure.

In alternate language, a “photodefinable layer” does not require the useof another material layer formed thereover, for example, a photoresistlayer, to form the aforementioned patterned layer or structure. It willbe further understood that a polymer composition having such acharacteristic is generally employed in a pattern forming scheme to forma patterned film/layer or structure. It will be noted that such a schemeincorporates an “imagewise exposure” of the photodefinable material orlayer formed therefrom. Such imagewise exposure being taken to mean anexposure to actinic radiation of selected portions of the layer, wherenon-selected portions are protected from such exposure to actinicradiation.

As used herein, the term “self-imageable compositions” will beunderstood to mean a material that is photodefinable and can thusprovide patterned layers and/or structures after direct image-wiseexposure of a film formed thereof followed by development of such imagesin the film using an appropriate developer.

By the term “derived” is meant that the polymeric repeating units areformed from, for example, condensation of a dianhydride with a diamine.That is, polyimide repeat units are derived from the correspondingdianhydride and diamine. Generally, such condensation reaction firstresults in a polyamic acid which is further condensed to form apolyimide as described further in detail below. Accordingly, a polyamicacid or a polyimide is generally derived from the condensation ofequimolar amounts of at least one dianhydride with one diamine. When amono-anhydride or a mono-amine is used off-setting the stoichiometry,the resulting polyimide will be end-capped with such excess amount ofeither the mono-anhydride or the mono-amine employed.

Thus, in accordance with the practice of this invention there isprovided an end capped polyamic acid of the formula (IA) or an endcapped polyimide of the formula (IB):

wherein:

m is an integer of at least 50;

X is one or more distinct tetravalent organic group;

Y is one or more distinct divalent organic group; and

R₁ and R₂ are the same or different and each independently of oneanother selected from the group consisting of linear or branched(C₁-C₁₆)alkenyl, hydroxy(C₁-C₁₂)alkenyl, perfluoro(C₁-C₁₂)alkenyl, and(C₆-C₁₀)aryl(C₁-C₃)alkenyl.

The polyamic acid of formula (IA) or polyimide of formula (IB) of thisinvention can be synthesized by any of the procedures known to oneskilled in the art. As noted above, such methods include condensation ofone or more dianhydrides with one or more diamines essentially inequimolar ratios. Further, suitable amounts of substituted unsaturatedcyclic anhydride of formula (II) is employed to end cap the resultingpolyamic acid or polyimide. Any of the dianhydrides or diamines incombination with substituted cyclic anhydride or their equivalentprecursor compounds can be employed.

More specifically, the dianhydrides and the diamines that are suitablefor forming the polyamic acid or polyimide of this invention can berepresented by the following general formulae (IC) and (ID).

Wherein X and Y are as defined herein. Thus, any of the dianhydrides oftetracarboxylic acids in combination with any of the diamines can beemployed to form the polyamic acid and subsequently the polyimides.Again, as noted, any of the techniques known in the art to makepolyimides and/or polyamic acid can be employed herein in combinationwith desirable amounts of the cyclic anhydride of formula (II).

Now turning specifically to X, any of the suitable tetravalent organicgroup can be employed herein. Non-limiting examples of such X may beselected from the group consisting of:

wherein

a is an integer from 0 to 4, inclusive;

is a single bond or a double bond;

each of R₃ is independently selected from the group consisting ofhydrogen, methyl, ethyl, linear or branched (C₃-C₆)alkyl,trifluoromethyl, pentafluoroethyl, linear or branchedperfluoro(C₃-C₆)alkyl, methoxy, ethoxy, linear or branched(C₃-C₆)alkyloxy, (C₂-C₆)acyl, (C₂-C₆)acyloxy, phenyl and phenoxy;

Z is a divalent group selected from the group consisting of:

(CR₄R₅)_(b), O(CR₄R₅)_(b), (CR₄R₅)_(b)O, (OCR₄R₅)_(d), (CR₄R₅O)_(d),(CR₄R₅)_(b)—O—(CR₄R₅)_(c), (CR₄R₅)_(b)—O—(SiR₄R₅)_(c),(CR₄R₅)_(b)—(CO)O—(CR₄R₅)_(c), (CR₄R₅)_(b)—O(CO)—(CR₄R₅)_(c),(CR₄R₅)_(b)—(CO)—(CR₄R₅)_(c), (CR₄R₅)_(b)—(CO)NH—(CR₄R₅)_(c),(CR₄R₅)_(b)—NH(CO)—(CR₄R₅)_(c), (CR₄R₅)_(b)—NH—(CR₄R₅)_(c), where b andc are integers which may be the same or different and each independentlyis 0 to 12, and d is an integer from 1 to 12, inclusive;

R₄ and R₅ are the same or different and each independently selected fromthe group consisting of hydrogen, methyl, ethyl, linear or branched(C₃-C₆)alkyl, trifluoromethyl, pentafluoroethyl, linear or branchedperfluoro(C₃-C₆)alkyl, methoxy, ethoxy, linear or branched(C₃-C₆)alkyloxy, (C₂-C₆)acyl, (C₂-C₆)acyloxy, phenyl and phenoxy.

Even more specifically, suitable dianhydrides may include the following:

Even more specifically, one or more of the dianhydrides of the followingformulae can also be employed herein.

Where a, Z and R₃ are as defined herein.

In some embodiments, the polyimide or polyamic acid of this inventionare formed using the dianhydrides where X is derived from one or moredianhydrides selected from the group consisting of:

-   1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA);

-   4-methyl-1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone;

-   5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA);

-   5,5′-(perfluoropentane-3,3-diyl)bis(isobenzofuran-1,3-dione);

-   5,5′-carbonylbis(isobenzofuran-1,3-dione) (BTDA);

-   5,5′-azanediylbis(isobenzofuran-1,3-dione);

-   [4,5′-biisobenzofuran]-1,1′,3,3′-tetraone (α-BPDA);

-   5,5′-oxybis(isobenzofuran-1,3-dione) (ODPA);

-   [5,5′-biisobenzofuran]-1,1′,3,3′-tetraone (BPDA); and

-   5-(2,5-dioxotetrahydrofuran-3-yl)-7-methyl-3a,4,5,7a-tetrahydroisobenzofuran-1,3-dione    (D1901).

As noted, again, any of the diamines known in the art can be used toform the polyamide or polyamic acid of this invention. The diamines canagain be broadly classified as aromatic diamines, aliphatic diamines ormixed aliphatic-aromatic diamines which contain a wide variety ofbridging groups. A non-limiting generic types of diamines include thefollowing:

Where a, Z and R₃ are as defined herein.

In some embodiments, the polyimide or polyamic acid of this inventionare formed using the diamines where Y is derived from one or morediamines selected from the group consisting of:

-   4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)    (6BF);

-   4,4′-(aperfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline    (HFBAPP);

-   2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB);

-   4,4′-oxydianiline (4,4′-ODA);

-   4,4′-(1,3-phenylenebis(oxy))dianiline (APB);

-   4,4′-methylenebis(2,6-dimethylaniline) (DO3);

-   2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5);

-   2-(4-aminophenyl)benzo[d]oxazol-6-amine (BZXPh-6);

-   benzo[d]oxazole-2,5-diamine (BZX-5);

-   benzo[d]oxazole-2,6-diamine (BZX-6);

-   bicyclo[2.2.1]heptane-2,5-diyldimethanamine (NBDA);-   a diamine of formula (IIIA)

where, n=2 to 6 (JD-230);

-   4,4′-(perfluoropropane-2,2-diyl)bis(2-aminophenol) (BAFA); and

-   4,4′-(propane-2,2-diyl)bis(2-aminophenol) (DABPA).

As noted, the polyamic acid or polyimide of this invention are endcapped with a suitable unsaturated cyclic anhydride. A suitable endcapped unsaturated cyclic anhydride group is derived from a compound offormula (II):

-   -   wherein R₁ and R₂ are as defined in claim 1.

Various compounds of formula (II) are well known in the art and arecommercially available or can be made readily following the proceduresreported in the art. For example, a compound of formula (II) where R₂ ishydrogen and R₁ is methylene (═CH₂), commonly known as itaconicanhydride, is commercially available from Sigma Aldrich. Similarly, acompound of formula (II) where R₂ is hydrogen and R₁ is isobutylene(—CH₂C(═CH₂)CH₃), 3-(2-methylallyl)dihydrofuran-2,5-dione (MP SA), iscommercially available from Combi Blocks.

Again, any of the unsaturated cyclic anhydride of formula (II) that willbring about the intended benefit can be employed herein. Non-limitingexamples of the compound of formula (II) is selected from the groupconsisting of:

-   itaconic anhydride (IA);

-   3-methyl-4-methylenedihydrofuran-2,5-dione;

-   3-(2-methylallyl)dihydrofuran-2,5-dione (MPSA); and

-   3-methyl-4-(2-methylallyl)dihydrofuran-2,5-dione.

The polyamic acid or the polyimide of this invention having suitablemolecular weight can be tailored based on the intended application byemploying appropriate polycondensation methods. Accordingly, in someembodiments the number of repeat units, m, in the resulting polyamicacid or the polyimide is at least 50; in some other embodiments m is atleast 100, 500, 1000, 2000 or higher. In some embodiments m is from 50to 2000, inclusive. The degree of polycondensation can be measured bydetermining the molecular weight of the resulting polyamic acid or thepolyimide using any of the known methods in the art, such as forexample, by gel permeation chromatography (GPC) equipped with suitabledetector and calibration standards, such as differential refractiveindex detector calibrated with narrow-distribution polystyrenestandards.

Accordingly, the polyamic acid or the polyimide of this inventiongenerally exhibit a weight average molecular weight (M_(w)) of at leastabout 5,000. In some other embodiments, the polyamic acid or polyimideas described herein exhibit a weight average molecular weight (M_(w)) ofat least about 20,000. In some other embodiments, the polyamic acid orpolyimide made in accordance of this invention has a M_(w) of at leastabout 50,000.

In yet another embodiment, the polyamic acid or polyimide of thisinvention has a M_(w) of at least about 100,000. In some otherembodiments, the polyamic acid or polyimide of this invention has aM_(w) of at least about 200,000. In some other embodiments, the polyamicacid or polyimide of this invention has a M_(w) ranging from about50,000 to 500,000, or higher.

The polyamic acid or polyimide of this invention generally contains anamic acid or imide repeat unit derived from at least one dianhydride andat least one diamine end capped with a cyclic anhydride of formula (II)as described herein. In some other embodiments, the polyamic acid or thepolyimide of this invention contains an amic acid or imide repeat unitsderived from two or more anhydrides and two or more diamines asdescribed herein, which is further end capped with the cyclic anhydrideof formula (II) as described herein. All of such permutation andcombinations are part of this invention. Generally, equimolar ratios ofdianhydrides and diamines are employed to form the polyamic acid or thepolyimide. That is, one mole of dianhydride is condensed with one moleof diamine. When two or more dianhydrides or diamines are employed, anyof the molar ratios of the respective two or more dianhydrides anddiamines can be employed so as to tailor the properties of the resultingpolyamic acid or the polyimide and depending upon the intendedapplications. In any event, the polyamic acid or the polyimide of thisinvention contains generally equal molar amounts of the totaldianhydride and the total diamines when more than one dianhydride ormore than one diamine is employed. That is, a polyamic or the polyimideof this invention is made by employing equimolar amounts of dianhydrideand diamine, which includes the molar amounts of the end capped cyclicanhydride of formula (II).

Non-limiting examples of a polyamic acid or a polyimide made inaccordance of this invention may be enumerated as follows:

A polyamic acid formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA).

A polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofiiran-1,3-dione) (6FDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA). A polyamic acid formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB) anditaconic anhydride (IA).

A polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB) anditaconic anhydride (IA).

A polyamic acid formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline(HFBAPP), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB)and itaconic anhydride (IA).

A polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline(HFBAPP), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB)and itaconic anhydride (IA).

A polyamic acid formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA).

A polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA).

Advantageously, several of the polyamic acid or the polyimide of thisinvention are soluble in an organic solvent. Exemplary organic solvents,without any limitation, that can be employed to dissolve the polyamicacid or the polyimide of this invention are selected from the groupconsisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL),N,N-dimethylacetarnide (DMAc), propylene glycol monomethyl ether acetate(PGMEA), dimethyl sulfoxide (DMSO), cyclopentanone, cyclohexanone,2-butanone and 2-heptanone and mixtures in any combination thereof. Asnoted, any of the aforementioned solvents can be used alone or incombination with one or more solvents.

Advantageously the polyimides of this invention exhibit very highthermo-mechanical properties. Specifically, it has now been found thatthe films formed from the polyimides of this invention exhibit excellenttensile properties as well as very high elongation to break (ETB). Thefilms can be readily formed from any of the known solvent castingmethods as well as melt extrusion methods. For example, the polyamicacid or polyimide of this invention can be coated onto a suitablesubstrate, such as for example, spin coating. The coated substrates arethen baked to remove any residual solvents especially in the case ofpolyimide coated substrate. The polyamic acid coated substrates arefurther baked to form the polyimide at a suitable temperature. Such postapply baking (PAB) temperatures can range from about 100° C. to 150° C.for a sufficient length of time from about 2 minutes to 30 minutes. Insome embodiments such PAB temperature is at about 110° C. for about 3minutes. The polyamic acid films so formed are then cured at atemperature in the range of from about 280° C. to 350° C. to form thepolyimide films for a sufficient length of time ranging from about 2hours to 4 hours under inert atmosphere, such as for example, nitrogenatmosphere. In some embodiments such curing is carried out at 320° C.for about 3 hours.

In some embodiments the films of polyimide polymers of this inventioncan be formed directly from the solutions of the respective polyimidepolymers by casting on to a suitable substrate. The polyimide polymercoated substrates are post apply baked (PAB) at temperatures rangingfrom about 100° C. to 150° C. for a sufficient length of time,typically, from about 2 minutes to 30 minutes. In some embodiments suchPAB temperature is at about 110° C. for about 3 minutes. The polyimidefilms so formed are then cured at a significantly lower temperature thanmentioned above, such as for example in the temperature range of fromabout 150° C. to 250° C. to form the fully cured polyimide films for asufficient length of time ranging from about 2 hours to 6 hours underinert atmosphere, such as for example, nitrogen atmosphere. In someembodiments such curing is carried out at 170° C. for about 4 hours. Insome other embodiments such curing is carried out at 220° C. for about 3to 4 hours.

The cured polyimide films can readily be lifted out of the substratesfor mechanical property testing. The tensile strength of the so formedfilms are generally in the range from about 100 MPa to about 250 MPadepending upon the type of dianhydrides and diamines employed to formthe polyimide. In some embodiments the tensile strength is from about150 MPa to about 200 MPa and in some other embodiments the tensilestrength is from about 160 MPa to about 180 MPa. The ETB of the filmsare generally high as well. The ETB can range from about 30 percent to100 percent or higher. In some embodiments the ETB ranges from about 40percent to 90 percent, 50 percent to 80 percent, and so on.

In a further aspect of this invention there is further provided acomposition comprising the polyamic acid or the polyimide of formulae(IA) or (IB) as described herein in combination with a photo radicalgenerator and a thermal radical generator. The compositions of thisinvention are photosensitive, and therefore, can be employed in avariety of optoelectronic application for forming a variety of polymericlayers, which may be patternable so as to find applications asdielectric materials.

The composition of this invention encompasses all of the polyamic acidsand polyimides as described hereinabove derived from any of thedianhydrides, diamines, and end capped with a unsaturated cyclicanhydride as described hereinabove and hereafter, including the specificpolyamic acids and the polyimides enumerated above and specificallyexemplified below.

Any of the photo radical generators that would provide the intendedbenefit can be employed. That is, the radicals generated by the photoradical generator will cause the photo radical crosslinking of thepolyamic acid and/or the polyimides of this invention with variousingredients used in the compositions of this invention so as to formpolymeric layers. In some embodiments, the composition of this inventionencompasses a photo radical generator selected from the group consistingof:

a compound of formula (IV):

wherein

R₆ and R₇ are the same or different and each independently of oneanother selected from the group consisting of hydrogen, linear orbranched (C₁-C₈)alkyl and (C₆-C₁₀)aryl, or R₆ and R₇ taken together withthe nitrogen atom to which they are attached to form a 5 to 7 memberedmonocyclic ring or 6 to 12 membered bicyclic ring, said ring optionallycontaining one or more heteroatoms selected from O and N, and said ringoptionally substituted with a group selected from the group consistingof linear or branched (C₁-C₈)alkyl, (C₆-C₁₀)aryl, halogen, hydroxy,linear or branched (C₁-C₅)alkoxy and (C₆-C₁₀)aryloxy; and

R₈, R₉ and R₁₀ are the same or different and each independently of oneanother is selected from the group consisting of hydrogen, linear orbranched (C₁-C₁₆)alkyl, (C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy,halogen, linear or branched (C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy; and

a compound of formula (V):

wherein

d is an integer from 0 to 3, inclusive;

R₁₁ is selected from the group consisting of hydrogen, linear orbranched (C₁-C₁₆)alkyl, (C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy,halogen, linear or branched (C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy;

R₁₂ is selected from the group consisting of linear or branched(C₁-C₁₆)alkyl, (C₃-C₅)cycloalkyl, (C₆-C₁₀)aryl,(C₆-C₁₀)aryl(C₁-C₃)alkyl, (C₆-C₁₀)aryl(C₁-C₆)alkylphosphinate,(C₆-C₁₀)heterocycle(C₁-C₃)alkyl, a group of formulaC(O)—(OCH₂CH₂)_(c)—OC(O)C(O)(C₆-C₁₀)aryl, where e is an integer from 2to 4, inclusive, C(O)C(O)O(C₁-C₃)alkyl and a group of formula (C):

wherein

R₁₃ is linear or branched (C₁-C₁₆)alkyl; and

R₁₄ is (C₆-C₁₀)aryl;

and where each of said alkyl, cycloalkyl, aryl and heterocycle mayadditionally be substituted with one or more groups selected from thegroup consisting of hydroxy, linear or branched (C₁-C₆)alkyl, linear orbranched (C₁-C₆)alkoxy and linear or branched thio(C₁-C₆)alkyl.

Non-limiting examples of the photo radical generator are enumerated asfollows:

-   (1-hydroxycyclohexyl)(phenyl)methanone (commercially available as    IRGACURE 184 from Ciba Specialty Chemicals);

-   2,2-dimethoxy-1,2-diphenylethan-1-one (commercially available as    IRGACURE 651 from Ciba Specialty Chemicals);

-   (phenylphosphoryl)bis(mesitylmethanone) (commercially available as    IRGACURE 819 from Ciba Specialty Chemicals);

-   (diphenylphosphoryl)(mesityl)methanone (commercially available as    DAROCUR TPO from Ciba Specialty Chemicals);

-   ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate (commercially    available as OMNIRAD TPO L from IGM Resins);

-   (diphenylphosphoryl)(mesityl)methanone;

-   2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one    (commercially available as Irgacure 369 from Ciba Specialty    Chemicals);

-   2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one    (commercially available as Irgacure 907 from Ciba Specialty    Chemicals);

-   oxybis(ethane-2,1-diyl) bis(2-oxo-2-phenylacetate) (commercially    available as Irgacure 754 from Ciba Specialty Chemicals);

-   (E)-2-((benzoyloxy)imino)-1-(4-(phenylthio)phenyl)octan-1-one    (commercially available as Irgacure OXE01 from Ciba Specialty    Chemicals);

-   methyl 2-oxo-2-phenylacetate (commercially available as DAROCUR MBF    from Ciba Specialty Chemicals);

-   benzophenone (commercially available as DAROCUR BP from Ciba    Specialty Chemicals);

-   2-hydroxy-2-methyl-1-phenylpropan-1-one (commercially available as    DAROCUR 1173 from Ciba Specialty Chemicals);

-   2-hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropan-1-one    (commercially available as lrgacure 2959 from Ciba Specialty    Chemicals);

-   2,2-dimethyl-1-phenylpropan-1-one;

and a mixture in any combination thereof.

It should be noted that more than one photo radical generator can beemployed so as to obtain beneficial effects. Accordingly, in someembodiments the composition of this invention contains two or more photoradical generators selected from the above list. Any of the suitableamounts of the photo radical generator can be employed in thecomposition of this invention which will bring about the intendedeffect. Generally, such amounts may vary from about 5 parts per hundredparts resin (pphr) to about 15 pphr or higher. In some embodiments theamount of photo radical generator employed is from about 8 pphr to about12 pphr.

The composition of this invention further includes a thermal radicalinitiator. Any of the compounds which when exposed to heat forms aradical can be employed for this purpose. Suitable generic classes ofsuch compounds include peroxides, peracids, azo compounds,N-alkoxyamines, N-acyloxyamines, and the like. Non-limiting examples ofsuch specific thermal radical generators include benzoyl peroxide,dicumyl peroxide, m-chloroperbenzoic acid, methyl ethyl ketone peroxide,azobisisobutyronitrile (AIBN), (1-phenyl-3,3-dipropyltriazene),(1-(phenyldiazenyl)pyrrolidine), (1-(phenyldiazenyl)piperidine),(1-(phenyldiazenyl)azepane) and the like.

Again, any of the suitable amounts of the thermal radical generator canbe employed in the composition of this invention which will bring aboutthe intended effect. Generally, such amounts may vary from about 2 partsper hundred parts resin (pphr) to about 10 pphr or higher. In someembodiments the amount of photo radical generator employed is from about3 pphr to about 6 pphr.

It has been further observed that employing one or more photosensitizersin the composition of this invention provides additional beneficialeffects. Most notably, the photosensitizers facilitate photo radicalgeneration from the photo radical generator at a particular wavelengthof the radiated light. For this purpose, any suitable sensitizercompound can be employed in the compositions of the present invention.Such suitable sensitizer compounds include, photosensitizers, such as,anthracenes, phenanthrenes, chrysenes, benzpyrenes, fluoranthenes,rubrenes, pyrenes, xanthones, indanthrenes, and mixtures thereof. Insome exemplary embodiments, suitable sensitizer components includemixtures thereof. Generally, as mentioned above, the photosensitizersabsorb energy from the radiated light source and transfers that energyto the photo radical generator of formulae (IV) or (V) employed in thecomposition of this invention so as to generate the radicals to initiatethe crosslinking. It has been now found that the photosensitizer asemployed herein may itself act as a photo radical generator.Accordingly, in some embodiments, the composition of this inventioncontains only one or more photosensitizers, which not only activates thecomposition at certain wavelength but also generates photo radicaltriggering the crosslinking. In some other embodiments the compositionof this invention contains one or more photo radical generators offormulae (IV) or (V) in combination with one or more photosensitizers offormula (VI) as described hereinbelow.

Accordingly, the composition of this invention contains one or more of aphotosensitizer of the formula (VI):

wherein

R₁₅ and R₁₆ are the same or different and independently of each otherselected from the group consisting of hydrogen, halogen, methyl, ethyl,linear or branched (C₃-C₁₂)alkyl, (C₃-C₁₂)cycloalkyl,(C₆-C₁₂)bicycloalkyl, (C₇-C₁₄)tricycloalkyl, (C₆-C₁₀)aryl,(C₆-C₁₀)aryl(C₁-C₃)alkyl, (C₁-C₁₂)alkoxy, (C₃-C₁₂)cycloalkoxy,(C₆-C₁₂)bicycloalkoxy, (C₇-C₁₄)tricycloalkoxy,(C₆-C₁₀)aryloxy(C₁-C₃)alkyl and (C₆-C₁₀)aryloxy.

Non-limiting examples of suitable one or more photosensitizers may beselected from the group consisting of:

-   1-chloro-4-methoxy-9H-thioxanthen-9-one;

-   1-chloro-4-ethoxy-9H-thioxanthen-9-one;

-   1-chloro-4-propoxy-9H-thioxanthen-9-one (commercially available as    CPTX from IGM resins);

-   1-chloro-2-propoxy-9H-thioxanthen-9-one;

-   1-chloro-2-ethoxy-9H-thioxanthen-9-one;

-   1-chloro-2-methoxy-9H-thioxanthen-9-one;

-   1-chloro-4-methyl-9H-thioxanthen-9-one;

-   1-chloro-4-ethyl-9H-thioxanthen-9-one;

-   1-bromo-4-propoxy-9H-thioxanthen-9-one;

-   1-chloro-4-phenoxy-9H-thioxanthen-9-one;

-   2,4-diethyl-9H-thioxanthen-9-one (commercially available as OMNIRAD    DETX from IGM resins); and

-   2-isopropyl-9H-thioxanthen-9-one (commercially available as OMNIRAD    ITX from IGM resins).

It should again be noted that any one of these compounds can be used asphotosensitizers alone or as mixtures in any combination thereof, andonly if needed depending upon the intended use and to obtain thedesirable benefit. Again, any amount of one or more of aforementionedsensitizers can be used in the composition of this invention so as tobring about the desired results. Generally it has now been found thatsuch amounts can range from 0.5 to 5 parts per hundred parts of thepolymer resin (pphr). In some embodiments such amounts range from 1 to 3pphr.

The compositions of the present invention also include one or morecrosslinking agents that are advantageously capable of bonding with theend-capped substituted unsaturated cyclic imide group of the polyamicacid or polyimide or any other functional group available in thepolymeric chain for further crosslinking when exposed to a suitableradiation. Such materials include, but are not limited to, crosslinkingcompounds that incorporate one or more of an oxazoline group such as2-oxazoline-2-yl group, a methylol group such as a N-hydroxymethylaminocarbonyl group or an alkoxymethyl group such as a N-methoxymethylaminocarbonyl group, acrylate group, thiol or thioalkyl group,maleimide, and the like.

Generally, the aforementioned bonding with the substituted unsaturatedcyclic imide end group of the polyimide is a cross-linking reaction thatis initiated by photo radical generated during the photo-irradiation atan appropriate temperature. Further, such crosslinking can be completedfurther by curing at an appropriate temperature post irradiation,generally at or above 150° C. for an appropriate amount of time. Suchthermal curing is further facilitated by thermal radical generator aswell as the thermal crosslinking agents such as for example, epoxygroups such as a glycidyl group, an epoxycyclohexyl group, an oxetanegroup, and the like. It should be noted however that it is surprisingthat such curing of the composition of this invention can be carried outat much lower temperature than conventionally used for polyimides knownin the art, which is generally carried out at higher than 250° C. oreven higher than 300° C.

Accordingly, in some embodiments of this invention, the photosensitivecomposition of this invention, without any limitation, contains one ormore crosslinking agents selected from the following:

an epoxy acrylate;

a polyester acrylate;

a polyether acrylate;

an aliphatic urethane acrylate;

an aromatic urethane acrylate;

a multifunctional epoxy; and

a multifunctional mercapto(C₂-C₈)alkanoate.

Exemplary crosslinking agents that may be employed in the composition ofthis invention without any limitation may be selected from the groupconsisting of:

-   (2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)tris(ethane-2,1-diyl)    triacrylate (TAEICY);

-   (oxybis(methylene))bis(2-ethylpropane-2,1,3-triyl) tetraacrylate    (BTMPTA);

-   2,2′-(((2-ethyl-2-((oxiran-2-ylmethoxy)methyl)propane-1,3-diyl)bis(oxy))bis(methylene))bis(oxirane)    (TMPTGE, from Nagase);

-   2,2-bis(((3-mercaptopropanoyl)oxy)methyl)propane-1,3-diyl    bis(3-mercaptopropanoate) (PET3MP); and

-   2,2,2′,2′-tetrakis(3-mercaptopropanoyl)-3,3′(3-mercaptopropanoyl)-1,1′-dipropyl    ether (DPEH3MP, from TCI).

The photosensitive composition of this invention further encompasses oneor more compounds or additives having utility as, among other things,adhesion promoter, a surface leveling agent, antioxidants, a synergist,silane coupling agents, phenolic resins, flame retardants, plasticizers,curing accelerators, and the like. Examples of surface leveling agentsinclude a variety of non-ionic, amphoteric and anionic surfactantsavailable in the art, which provide, among other things, wetting,spreading and levelling properties. Exemplary surface leveling agentsinclude without any limitation, non-ionic polymeric fluorochemicalsurfactant, such as for example, FC-4432 available from 3M AdvancedMaterials Division, a short chain perfluoro-based ethoxylated nonionicfluorosurfactant, such as for example, Chemguard S-550, CAPSTONEfluorosurfactants available as both nonionic and amphoteric forms fromDuPont, PolyFox fluorosurfactants from OMNOVA Solutions, and the like.In addition, any of the known conventional surfactants may be used incombination with the above noted surfactants, such known non-ionicsurfactants include for example, perfluoroalkyl polyoxyethyleneethanols, fluorinated alkyl esters, perfluoroalkylamine oxides andfluorinated organosiloxane compounds. Various other such commerciallyavailable surfactants include Florade FC-4430 from Sumitomo 3M Ltd.,Surflon S-141 and S-145 from Asahi Glass Co., Ltd., Unidyne DS-401,DS-4031 and DS-451 from Daikin Industries Ltd., Megaface F-8151 fromDainippon Ink & Chemicals, Inc., and X-70-093 from Shin-Etsu ChemicalCo., Ltd.

Non-limiting examples of such other compounds or additives are selectedfrom the group consisting of the following, commercially availablematerials are indicated by such commercial names.

-   triethoxy(3-(oxiran-2-ylmethoxy)propyl)silane, also known as    3-glycidoxypropyl triethoxysilane (3-GTS or (KBE-403 from Shin-Etsu    Chemical Co., Ltd.));

-   trimethoxy(3-(oxiran-2-ylmethoxy)propyl)silane, also commonly known    as 3-glycidoxypropyl trimethoxysilane (KBM-403E from Shin-Etsu    Chemical Co., Ltd.));-   C₆H₅(CH₃O)₃Si-   phenyltrimethoxysilane-   C₆H₅(C₂H₅O)₃Si-   phenyltriethoxysilane (KBE-103 commercially available from Gelest or    Shin-Etsu Chemical Co., Ltd.)

-   3,3,10,10-tetramethoxy-2,11-dioxa-3,10-disiladodecane (SIB-1832 from    Gelest);

-   N,N′-bis[(3-triethoxysilylpropyl)aminocarbonyl]polyethylene oxide    (SIB-1824.84 from Gelest);

-   diethoxy(propoxy)(3-thiocyanatopropyl)silane (SIT 7908.0 from    Gelest);

-   4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane;

-   3,3,12,12-tetramethoxy-2,13-dioxa-7,8-dithia-3,12-disilatetradecane    (Si-75 or Si-266 from Evonik);

-   2,2′-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(4-methylphenol)    (antioxidant AO-80 from TCI Japan)

In general among other things, various compounds and additives asenumerated herein improve overall performance of the photosensitivecomposition of this invention thus providing well definedphoto-patterned structures having a variety of utilities, including butnot limited to chip-stack applications, redistribution layers (RDL) andfor forming CMOS image sensor dam structures. Advantageously, it hasalso been found that certain of the additives as described herein mayfeature more than one function. For example, some of the additives asenumerated hereinabove may not only exhibit certain photosensitizationactivity during exposure to radiation but may also facilitate as a crosslinking agent as further described above. Therefore, additives as usedherein do not limit the activity of such compounds to only one of suchproperty but may also facilitate other functions of the photosensitivecompositions of this invention.

The photosensitive composition embodiments, in accordance with thepresent invention, are first applied to a desired substrate to form afilm. Such a substrate includes any appropriate substrate as is, or maybe used for electrical, electronic or optoelectronic devices, forexample, a semiconductor substrate, a ceramic substrate, a glasssubstrate. With regard to said application, any appropriate coatingmethod can be employed, for example, spin coating, spraying, doctorblading, meniscus coating, ink jet coating and slot coating.

Next, the coated substrate is heated to facilitate the removal ofresidual casting solvent, for example to a temperature from 70° C. to130° C. for from 1 to 30 minutes, although other appropriatetemperatures and times can be used. After the heating, the film isgenerally imagewise exposed to an appropriate wavelength of actinicradiation, wavelength is generally selected based on the choice of thephoto radical generator and/or photosensitizer incorporated into thepolymer composition as described herein. However, generally suchappropriate wavelength is from 200 to 700 nm. It will be understood thatthe phrase “imagewise exposure” means exposing through a masking elementto provide for a resulting pattern of exposed and unexposed portion ofthe film, as further illustrated by specific examples hereinbelow.

After an imagewise exposure of the film formed from photosensitivecomposition in accordance with the present invention, a developmentprocess is employed. For the negative tone compositions as contemplatedby the present invention, such development process removes only theunexposed portions of the film thus leaving a negative image of themasking layer in the film. A post exposure bake (PEB) is employed priorto the aforementioned development process, generally at a temperaturefrom 90° C. to 130° C. for from 1 to 10 minutes, although otherappropriate temperatures and times can be used.

Suitable developers can include organic solvents such as propyleneglycol methyl ether acetate (PGMEA), 2-heptanone, cyclohexanone, NMP,GBL, cyclopentanone, butyl acetate, and mixtures in any combinationthereof, among others.

Thus some composition embodiments of the present invention provideself-imageable films that after imagewise exposure, the resulting imageis developed using an organic solvent. After the image is developed, thesubstrate is rinsed to remove excess developer solution, typical rinseagents are water or appropriate alcohols and mixtures thereof. Theexcess developer can also be removed by blowing a stream of nitrogen onto the substrate. Other methods of removing excess developer includespinning the developed wafer at high spin speeds of about 1000-3000 rpmfor 10-30 sec followed by applying a stream of nitrogen.

After the aforementioned rinsing, the substrate is dried and the imagedfilm finally cured. That is to say, the image is fixed. Where theremaining layer has already been exposed during the imagewise exposure,image fixing is generally accomplished by causing further reactionwithin the remaining portions of the film. Such reaction is generally across-linking reaction that can be initiated by heating and/ornon-imagewise or blanket exposure of the remaining material. Suchexposure and heating can be in separate steps or combined as is foundappropriate for the specific use of the imaged film. The blanketexposure is generally performed using the same energy source as employedin the imagewise exposure or a higher energy source and may be for alonger period of time although any other appropriate energy source canbe employed. The heating is generally carried out at a desirabletemperature, for example, from above 150° C. for a time of from 40 minto one or more hours. Where the remaining layer has been exposed duringthe imagewise exposure, image fixing is generally accomplished by aheating step to be tailored to complete any reaction initiated by theexposure. However an additional blanket exposure and heating, asdiscussed above, can also be employed. It should be realized, however,that the choice of a final cure process is also a function of the typeof device being formed; thus a final fixing of the image may not be afinal cure where the remaining layer is to be used as an adhesive layeror structure.

The devices are produced by using embodiments of the composition of thepresent invention to form layers which are characterized as having highheat resistance, an appropriate water absorption rate, hightransparency, and low permittivity. In addition, such layers generallyhave an advantageous thermo-mechanical properties. Most notably,improved tensile strength, improved elongation to break (ETB) andexhibit higher glass transition temperatures (T_(g)) when compared withconventional materials. For example, the tensile strength of the fullycured composition layer may be higher than 100 MPa and may be in therange of from about 120 MPa to 200 MPa or higher. The ETB of the curedcomposition layers can be higher than 30 percent and may range fromabout 50 percent to 100 percent or higher. The T_(g) of the curedcomposition layer may be higher than 150° C. and can range from about150° C. to 200° C. or higher. It should further be noted that the layersformed in this fashion from the composition of this invention alsoexhibit unusually high thermal decomposition temperature. Accordingly,the 5 percent weight loss temperature (To) of the cured polymeric layersis generally higher than 300° C. and can range from 300° C. to 420° C.or higher, thus offering hitherto unattainable properties.

As previously mentioned, exemplary applications for embodiments of thephotosensitive compositions in accordance with the present inventioninclude die attach adhesive, wafer bonding adhesive, insulation films(interlayer dielectric layers), protecting films (passivation layers),mechanical buffer films (stress buffer layers) or flattening films for avariety of semiconductor devices, and printed wiring boards. Specificapplications of such embodiments encompass a die-attach adhesive to forma single or multilayer semiconductor device, dielectric film which isformed on a semiconductor device; a buffer coat film which is formed onthe passivation film; an interlayer insulation film which is formed overa circuit formed on a semiconductor device.

Accordingly, some embodiments in accordance with the present inventiontherefore provide a negative tone photosensitive polymer compositionwhich exhibits enhanced characteristics with respect to one or more ofmechanical properties (such as high tensile strength, elongation tobreak) and at least equivalent or better chemical resistance, ascompared to alternate materials. In addition, such embodiments providegenerally excellent electrical insulation, adhesion to the substrate,and the like. Thus semiconductor devices, device packages, and displaydevices are provided that incorporate embodiments in accordance with thepresent invention.

Advantageously, the photosensitive compositions of this invention canalso be used to form adhesive layers for bonding the semiconductor chipsto each other, such as in chip-stack applications. For example, abonding layer used for such a purpose is composed of a cured product ofthe photosensitive adhesive composition of the present invention. Itshould be noted that although the adhesive layer is a single-layerstructure, it can not only exhibit sufficient adhesiveness to thesubstrate but also it is expected to be free of significant stressresulting due to the curing step. Accordingly, it is now possible toavoid undesirably thick layer of film encompassing the chip as alaminate. Therefore, it should be noted that the laminates formed inaccordance with the present invention are expected to be reliable inthat the relaxation of stress concentration between layers caused bythermal expansion difference or the like can be obtained. As a result,the semiconductor device having low height and high reliability can beobtained. That is, devices with low aspect ratio and low thickness canbe obtained. Such semiconductor device becomes particularly advantageousto electronic equipment, which has very small internal volume and is inuse while carrying as a mobile device, for example. Even moreadvantageously, by practice of this invention it is now possible to forma variety of electronic devices featuring hitherto unachievable level ofminiaturization, thinning and light-weight, and the function of thesemiconductor device is not easily damaged even if such devices aresubject to rugged operations such as swinging or dropping.

A cured product of the photosensitive adhesive composition of thepresent invention, i.e., the adhesive layer or the film generallyexhibits an indentation modulus of 2 to 4 GPa at 25° C. The curedproduct of the photosensitive adhesive composition of the presentinvention exhibits an indentation modulus of 70 to 120% of theindentation modulus of the non-cured product at 25° C., i.e., beforesuch curing step. Further, the photosensitive adhesive composition ofthe present invention exhibits an excellent adhesiveness to a suitablesubstrate, such as for example a semiconductor chip, and adhesiveness of20 to 200 Newton (N) at 25° C. can be achieved before curing andgenerally after etching and ashing process.

Thus, it is now envisioned that the photosensitive adhesive compositionof the present invention may exhibit an indentation modulus at roomtemperature after curing which is relatively comparable to theindentation modulus of the uncured sample and not causing significantstress concentration between the semiconductor chips but contributing toforming of the adhesive layer with sufficient adhesiveness. Further,since the indentation modulus in a state before cured is within thepredetermined range of indentation modulus after cured, and then, forexample, it is not so possible that the photosensitive adhesivecomposition before cured is significantly deformed or flowed out, it ispossible to increase the accuracy of alignment in laminating thesemiconductor chips. Furthermore, since the change in indentationmodulus before and after curing is relatively small, the shrinkageassociated with photosensitivity can be reduced and then the stress atthe interface between the semiconductor chips caused by shrinkage oncuring can be reduced. This point also contributes to improvement of thereliability of the chip laminate.

Further, in some embodiments of this invention as described above, theelectronic and/or the semiconductor device according to this inventionencompass a laminated semiconductor element where said laminationconsists of a photosensitive composition according to the presentinvention.

In some embodiments of this invention, the semiconductor deviceencompassing a redistribution layer (RDL) structure further incorporatesa photosensitive composition according to this invention.

Further, in some embodiments of this invention as described above, thesemiconductor device encompassing a chip stack structure furtherincludes a photosensitive composition according to this invention.

In yet some other embodiments of this invention as described above, thesemiconductor device encompassing a complementary metal oxidesemiconductor (CMOS) image sensor dam structure further incorporates aphotosensitive composition according to this invention.

In addition, in some embodiments of this invention as described above, afilm is formed by the photosensitive composition according to thisinvention. As further described above, such films generally exhibitexcellent chemical, mechanical, elastic properties having a wide varietyof utility in electronic, optoelectronic, microelectromechanicalapplications featuring excellent dielectric properties.

Accordingly, in some embodiments of this invention, there is provided amicroelectronic or optoelectronic device encompassing one or more of aredistribution layer (RDL) structure, a chip-stack structure, a CMOSimage sensor dam structure, where said structures further incorporates aphotosensitive composition according to this invention.

Further, in some embodiments of this invention, there is provided amethod of forming a film for the fabrication of a microelectronic oroptoelectronic device comprising:

coating a suitable substrate with a composition according to theinvention to form a film;

patterning the film with a mask by exposing to a suitable radiation;

developing the film after exposure to form a photo-pattern; and

curing the film by heating to a suitable temperature.

The coating of the substrate with photosensitive composition of thisinvention can be performed by any of the coating procedures as describedherein and/or known to one skilled in the art, such as by spin coating.

In another aspect of this invention there is also provided a curedproduct comprising the composition of this invention.

This invention is further illustrated by the following examples whichare provided for illustration purposes and in no way limit the scope ofthe present invention.

EXAMPLES (GENERAL)

The following abbreviations have been used hereinbefore and hereafter indescribing some of the compounds, instruments and/or methods employed toillustrate certain of the embodiments of this invention:

-   6FDA—5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione);-   PMDA—1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone;-   6BF—4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline);-   BZXPh-5—2-(4-aminophenyl)benzo[d]oxazol-5-amine;-   PFMB—2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine;-   HFBAPP—4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline;-   NBDA—bicyclo[2.2.1]heptane-2,5-diyldimethanamine;

IA—itaconic anhydride;

-   IRGACURE    369—2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one;-   DCP—dicumyl peroxide;-   CPTX—1-chloro-4-propoxy-9H-thioxanthen-9-one;-   BTMPTA—(oxybis(methylene))bis(2-ethylpropane-2,1,3-triyl)    tetraacrylate;-   TAEICY—(2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)tris(ethane-2,1-diyl)    triacrylate;-   DPEH3MP—2,2,2′,2′-tetrakis(3-mercaptopropanoyl)-3,3′(3-mercaptopropanoyl)-1,1′-dipropyl    ether;-   KBM-403E—trimethoxy(3-(oxiran-2-ylmethoxy)propyl)silane;-   FC-4432—a non-ionic polymeric fluorochemical surfactant;-   NMP—N-methyl-2-pyrrolidone;-   GBL—γ-butyrolactone;-   DMAc—N,N-dimethylacetamide;-   DMSO—dimethyl sulfoxide;-   THF—tetrahydrofuran;-   GPC—gel permeation chromatography;-   M_(w)—weight average molecular weight;-   M_(n)—number average molecular weight;-   PDI—polydispersity index;-   ¹H-NMR—proton nuclear magnetic resonance spectroscopy;-   FT-IR—Fourier transform infrared spectroscopy;-   ppm—parts per million;-   pphr—parts per hundred parts of resin.

Example 1 6FDA/6BF/BZXPh-5/1A (48.1/29.6/19.8/2.5)

A mixture of 6BF (15.13 g, 30 mmol), BZXPh-5 (4.5 g, 20 mmol) and IA(0.28 g, 2.5 mmol) were dissolved in NMP (165.1 g) and stirred atambient temperature under a nitrogen atmosphere. To this solution wasthen added 6FDA (21.63 g, 48.7 mmol) in small batches while stirringthat generated about 5° C. exotherm. The reaction mixture was continuedto stir at ambient temperature for 20 hours during which time thesolution turned viscous. A small portion of this solution was dilutedwith DMAc for GPC analysis. GPC-DMAc—M_(w)=99,600, M_(n)=47,850,PDI=2.08.

The polyamic acid solution (127 g containing about 25 g polymer) thusobtained above was mixed with anhydrous pyridine (25 g), aceticanhydride (25 g) and cyclopentanone (100 g) and the solution heated to90° C. for 4 hours under nitrogen atmosphere while stirring. Thereaction mixture was allowed to cool to ambient temperature and added toexcess water/methanol (80/20) mixture (1.5 L) to isolate the polymer.The gummy product was washed with excess (1 L) heptanes and dried in avacuum oven at 80° C. for 24 hours to obtain a solid product (23 g, 92%isolated yield), which was characterized by GPC, ¹H NMR and FT-IR.GPC-DMAc—M_(w)=99,900, M_(n)=44,400, PDI=2.25. ¹H-NMR (500 MHz) spectrameasured in deuterated DMSO showed only traces of a peak centered atabout 10.4 ppm indicating that the polyamic acid was quantitativelyimidized. Multiple peaks were observed at 6.7-8.6 ppm for the aromaticprotons. FT-IR spectra showed peaks at 1379 cm⁻¹ and 722 cm⁻¹characteristic of polyimides.

Example 2 6FDA/PM DA/6BF/PFMB/IA (24.1/24.1/29.6//19.7/2.5)

6BF (15.13 g, 30 mmol) and PFMB (6.41 g, 20 mmol) were dissolved in NMP(150.7 g) and stirred at ambient temperature under a nitrogenatmosphere. A mixture of 6FDA (10.83 g, 24.4 mmol), PMDA (5.317 g, 24.4mmol) and IA (0.28 g, 2.5 mmol) was added in small batches to the abovesolution while stirring. The reaction mixture was stirred at ambienttemperature for an additional period of 20 hours during which time thesolution turned viscous. An additional amount of NMP (33 g) was added tothis viscous solution. A small portion of this solution was then dilutedwith DMAc for GPC analysis. GPC-DMAc—M_(w)=107,050, M_(n)=60,700,PDI=1.76. A small sample of the polymer solution was also added toexcess water/acetone (80/20) mixture to isolate the polymer for ¹H NMRanalysis. The gummy product was washed with excess water/acetone (80/20)mixture and dried in a vacuum oven at 50-60° C. for 24 hours to obtain asolid product. ¹H-NMR (500 MHz) spectra measured in deuterated DMSOshowed a broad peak centered at about 13.5 ppm for COOH and 10.99 ppm,10.88 ppm, and 10.86 ppm for —NH— groups of the polyamic acid inapproximately 1:1 ratio. Multiple peaks were observed at 6.7-8.7 ppm forthe aromatic protons from 6FDA, PMDA PFMB and 6BF.

The polyamic acid solution (65 g containing about 11 g polymer) thusobtained was then mixed with anhydrous pyridine (11 g), acetic anhydride(11 g) and cyclopentanone (62 g) and the solution was heated to 90° C.for 6 hours under nitrogen atmosphere while stirring. The reactionmixture was allowed to cool to ambient temperature and THF (25 g) wasadded. This solution was added to excess water/methanol (80/20) mixture(1.7 L) to isolate the polymer. The gummy product was washed with excess(1.2 L) water/methanol (80/20) mixture and dried in a vacuum oven at 70°C. for 24 hours to obtain a solid product (10.4 g, 95% isolated yield),which was characterized by GPC and ¹H NMR. GPC-DMAc—M_(w)=143,800,M_(n)=66,150, PDI=2.17. ¹H-NMR (500 MHz) spectra measured in deuteratedDMSO did not show a broad peak centered at about 13.5 ppm for COOH or10-11 ppm for —NH— groups indicating that the polyamic acid wasquantitatively imidized. Multiple peaks were observed at 6.7-8.7 ppm forthe aromatic protons from 6FDA, PMDA PFMB and 6BF. FT-IR spectra showedpeaks at 1374 cm⁻¹ and 723 cm⁻¹ characteristic of polyimides.

Example 3 6F DA/PMDA/HFBAPP/PFMB/IA (24.1/24.1/26.6/19.7/2.5)

HFBAPP (7.78 g, 15 mmol) and PFMB (3.2 g, 10 mmol) were dissolved in NMP(76.2 g) and stirred at ambient temperature under a nitrogen atmosphere.A mixture of 6FDA (5.41 g, 12.2 mmol), PMDA (2.66 g, 12.2 mmol) and IA(0.140 g, 1.25 mmol) was added in small batches to the above solutionwhile stirring. The reaction mixture was stirred at ambient temperaturefor 20 hours during which time the solution turned viscous. Anadditional amount of NMP (21 g) was added to the viscous solution. Asmall portion of this solution was then diluted with DMAc for GPCanalysis. GPC-DMAC—M_(w)=74,650, M_(n)=38,400, PDI=2.05.

The polyamic acid solution (100 g containing about 16 g polymer) thusobtained above was mixed with anhydrous pyridine (16 g), aceticanhydride (16 g) and cyclopentanone (75 g) and the solution was heatedto 90° C. for 6 hours under nitrogen atmosphere while stirring. Thepolymer became insoluble as the imidization progressed.

Example 4 6FDA/PMDA/6BF/BZXPh-5/IA (29/19.1/29.6/19.8/2.5)

6BF (10.6 g, 21 mmol) and BZXPh-5 (3.15 g, 14 mmol) were dissolved inNMP (103.4 g) and stirred at ambient temperature under a nitrogenatmosphere. A mixture of 6FDA (9.14 g, 20.6 mmol), PMDA (2.96 g, 13.6mmol) and IA (0.196 g, 1.75 mmol) was added in small batches to theabove solution while stirring. The reaction mixture was stirred atambient temperature for 20 hours during which time the solution turnedviscous. An additional amount of NMP (25 g) was added to this viscoussolution. A small portion of this solution was then diluted with DMAcfor GPC analysis. GPC-DMAc—M_(w)=103,700, M_(n)=54,200, PDI=1.91.

The polyamic acid solution (118 g containing about 20 g polymer) thusobtained above was mixed with anhydrous pyridine (20 g), aceticanhydride (20 g) and cyclopentanone (88 g) and the solution heated to95° C. for 2 hours under nitrogen atmosphere while stirring. The polymerbecame insoluble as the imidization progressed.

Example 5 6FDA/6BF/NBDA/MPSA (45/40/10/10)

6BF (15.13 g, 30 mmol) and NBDA (1.157 g, 7.5 mmol) were dissolved inNMP (125.1 g) and stirred at ambient temperature under a nitrogenatmosphere. To this solution was added a mixture of 6FDA (14.99 g, 33.8mmol) and MPSA (1.157 g, 25 mmol) in small batches while stirring. Thereaction mixture was continued to stir at ambient temperature for 20hours during which time the solution turned viscous. A small amount ofthis solution was diluted with DMAc for GPC analysis.GPC-DMAc—M_(w)=44,950, M_(n)=24,250, PDI=1.85. A small sample of thepolymer solution was added to excess heptane to isolate the polymer. Thegummy product was washed with excess heptane and dried in a vacuum ovenat 70° C. for 24 hours to obtain a solid product. ¹H-NMR (500 MHz)spectra measured in deuterated DMSO showed a broad peak centered atabout 13 ppm for COOH and 10.9 ppm, and 10.3 ppm for —NH— groups of thepoly(amic acid). Multiple peaks were observed at 6.7-8.7 ppm for thearomatic protons from 6FDA and 6BF.

Example 6 Tensile Property Measurements

Each of the polyimide formed in Example 1 and Comparative Example 1 weredissolved in a solvent mixture of GBL and cyclopentanone solvent mixture(3:1 weight ratio) to form respectively 20 weight percent solution forpolymer of Example 1 and 15 weight percent solution for polymer ofComparative Example 1. Portions of these solutions were mixed with DCP(6 pphr) and filtered using 0.45 μm pore polytetrafluoroethylene (PTFE)disc filters. The polyimide polymer solutions from Example 1 andComparative Example 1 containing no DCP were also filtered using 0.45 μmpore polytetrafluoroethylene (PTFE) disc filters. These four polymersolutions were spin coated separately on to a 4″ bare Si wafers byspinning at 300-310 rpm for 30 seconds followed by post apply bake (PAB)at 110° C. for 3 minutes to generate films in 10-14 μm range. The filmswere then cured at 220° C. for 4 hours in an oven under nitrogenatmosphere. The cured films were subsequently diced to 6 mm wide filmstrips and lifted out of the bare Si wafers by immersing in a dilute (1wt. %) hydrogen fluoride (HF) solution in water. Tensile properties weremeasured using Instron and the results are summarized in Table 1. It isevident from the data presented in Table 1 that the tensile strength ofExample 1 with DCP is substantially higher than that of the ComparativeExample 1, thus demonstrating that the incorporation of IA as an end capsubstantially increases the tensile property. In addition, incorporationof DCP further increases the tensile strength without causing anyadverse effects on other properties.

TABLE 1 Tensile Tensile ETB Polymer DCP Strength Strength ETB % Max, CTET_(g) T_(d5) Example No. present MPa, (SD) Max, MPa (SD) % ppm/K (° C.)(° C.) Comp. Ex. 1 No 118 (6) 125 20 (8) 28 50 273 nm Comp. Ex. 1 Yes110 (7) 117 13 (5) 19 45 264 573 Example 1 No 116 (2) 119 20 (5) 27 34267 nm Example 1 Yes 131 (7) 137 13 (3) 18 41 269 575 SD—standarddeviation; ETB—elongation to break; CTE—coefficient of thermalexpansion; T_(g)—glass transition temperature; T_(d5)—temperature atwhich the material loses 5% of its weight; nm—not measured.

Example 7 Photosensitive Compositions—Thermo-mechanical Properties

Isolated polyimide polymer from Example 1 was dissolved in a mixture ofGBL/cyclopentanone (3:1 weight ratio) to prepare 16 wt. % polymersolution. To this solution was added Irgacure-369 as a photo radicalgenerator (10 pphr), CPTX as the photo-sensitizer (2 pphr), KBM-403E asthe adhesion promoter (5 pphr) and FC-4432 as the surface leveling agent(0.3 pphr). This solution was then formulated into four differentcompositions by adding (DCP, 4 pphr) as a thermal radical initiator intotwo of these four compositions and also adding two different types ofacrylate cross linkers as summarized in Table 2.

TABLE 2 Composition Ex. No. DCP BTMPTA TAEICY Example 6A — 70 pphr —Example 6B 4 pphr 70 pphr — Example 6C — — 70 pphr Example 6D 4 pphr —70 pphr

The compositions thus formed in Examples 6A to 6D were filtered using0.45 μm or 1 μm pore polytetrafluoroethylene (PTFE) disc filters. Thesecompositions were spin coated on 4″ bare Si wafers by spinning at500-800 rpm for 30 seconds followed by post apply bake (PAB) at 110° C.for 3 minutes to generate films in 15-23 μm range. The films were thenexposed using a broad band Hg-vapor light source (at 365 run using aband pass filter) at an exposure dose of 1500 mJ/cm². The exposed filmswere cured at 170° C. for 4 hours in an oven under nitrogen atmosphere.The cured films were subsequently diced to 6 mm wide film strips andlifted out of the bare Si wafers by immersing in a dilute (1 wt. %)hydrogen fluoride (HF) solution in water. Tensile and thermal propertieswere measured using Instron and TMA respectively. The results aresummarized in Table 3. It is evident from the data presented in Table 3that the use of DCP in the compositions of this invention as a thermalradical initiator increases both tensile strength and the glasstransition temperature of the films so generated.

TABLE 3 Composition Tensile Strength ETB T_(g) Example No. DCP (MPa),(SD) (%), (SD) (° C.) Example 6A — 109 (0.5) 13 (7) 187 Example 6B 4pphr 116 (0.6) 17 (8) 218 Example 6C — 129 (4) 6 (1) 172 Example 6D 4pphr 141 (8) 7 (2) 204

Example 8 Photosensitive Compositions—Thermo-Mechanical Properties

Isolated polyimide polymers from Comparative Example 1 and Example 2were dissolved separately in a mixture of GBL and cyclopentanone (3:1weight ratio) to prepare 15-20 wt. % solutions. To these solutions wereadded Irgacure-369 as a photo radical generator (10 pphr), CPTX as thephoto-sensitizer (2 pphr), BTMPTA as an acrylate cross linker (30 pphr),TAEICY (30 pphr) as an acrylate cross linker, KBM-403E as the adhesionpromoter (5 pphr), FC-4432 as the surface leveling agent (0.3 pphr) anddicumyl peroxide (DCP) as the thermal radical initiator (4 pphr). Thesecompositions were filtered using 0.45 μm pore polytetrafluoroethylene(PTFE) disc filters and kept refrigerated before use, and designatedrespectively as Example 7A (polymer of Comparative Example 1), Example7B (polymer of Example 1) and Example 7C (polymer of Example 2).

Each of the above three compositions were spin coated on 4″ bare Siwafers by spinning at 300-800 rpm for 30 seconds followed by post applybake (PAB) at 110° C. for 3 minutes to generate films having thicknessin the range of 10-13 μm. The films were then exposed using a broad bandHg-vapor light source (at 365 nm using a band pass filter) at anexposure doses of 3500 mJ/cm² (for Examples 7A and 7B) or 1500 mJ/cm²(for Example 7C). The exposed films were cured at 220° C. for 4 hours(for Examples 7A and 7B) or 170° C. for 4 hours (for Example 7C) in anoven under nitrogen atmosphere. The cured films were subsequently dicedto 6 mm wide film strips and lifted out of the bare Si wafers byimmersing in a dilute (1 wt. %) hydrogen fluoride (HF) solution inwater. Tensile and thermal properties were measured using Instron andTMA or TGA respectively. The results are summarized in Table 4. It isagain evident that the IA end capped polymers, namely Examples 1 and 4,exhibit superior mechanical properties when compared with that of theComparative Example 1.

TABLE 4 Polymer example Comp. Ex. 1 Example 1 Example 4 Cure condition,° C./hours 220/4 220/4 170/4 Tensile Strength, MPa (SD) 112 (7) 129 (11)122 (7) Tensile Strength (max), MPa 121 144 131 ETB, % (SD) 9 (2) 6 (1)35 (26) ETB (max), %  11  7  62 Young's Modulus, GPa 3.0 (0.2) 3.5 (0.3)3.3 (0.2) CTE, ppm/K  61  69  29 T_(g), ° C. 230 226 183 T_(d5), ° C.428 433 355

The compositions as formed above were spin coated on 4″ SiO₂ wafers byspinning at 1300-1700 rpm for 30 seconds followed by post apply bake(PAB) at 110° C. for 3 minutes to generate films of thickness in 2-4 μmrange. The films were then exposed using a broad band Hg-vapor lightsource (at 365 run using a band pass filter) at an exposure dose of0-2500 mJ/cm² through a mask to generate negative tone images of lines,trenches, pillars and holes followed by a post exposure bake (PEB) at110° C. for 2 minutes. These films were immersed in cyclopentanone for30-35 seconds to reveal the lines (L), pillars (P) and holes (H). Holeswere not opened for the films from composition Examples 7A and 7C. Thephoto imaging properties are summarized in Table 5.

TABLE 5 Composition FT Dose BFL Resolution Example No. μm mJ/cm² %L/P/H, μm Example 7A 3.64 2500 62% 15/15/— Example 7B 2.54 2418 29% 7/10/10 Example 7C 2.41 2500 57% 10/10/—

Top down optical micrograph images from the photo imaging of thecomposition Example 7B are shown in FIGS. 1 to 3. FIG. 1 shows the topdown view of the lines. FIG. 2 shows the top down view of the pillars.FIG. 3 shows the top down view of the holes.

Example 9 Photosensitive Compositions

Polyamic acid polymer solution before isolation from Example 5 in NMP(15 wt. % solution) was used to prepare two photosensitive compositions,9A and 9B. To this solution was added Irgacure-369 as a photo radicalgenerator (10 pphr), CPTX as the photo-sensitizer (2 pphr), BTMPTA as anacrylate cross linker (50 pphr), KBM-403E as the adhesion promoter (5pphr) and FC-4432 as the surface leveling agent (composition 8A).DPEH3MP (50 phr) was also added to composition Example 9B as a thiolcross linker. These compositions were filtered using 0.45 μm porepolytetrafluoroethylene (PTFE) disc filters and kept refrigerated beforeuse, and designated respectively as Example 9A (contained only BTMPTA asan acrylate cross linker) and Example 9B (contained BTMPTA as anacrylate cross linker and DPEH3MP as a thiol cross linker).

Each of the above two compositions were spin coated on 4″ SiO₂ wafers byspinning at 900-1200 rpm for 30 seconds followed by post apply bake(PAB) at 110° C. for 3 minutes to generate films having thicknesses inthe range of 5-7 μm. The films were then exposed using a broad bandHg-vapor light source (at 365 nm using a band pass filter) at anexposure dose of 0-2000 mJ/cm² through a mask to generate negative toneimages of lines (L), pillars (P) and holes (H). The exposed films werepost exposure baked (PEB) at 110° C. for 2 minutes. These films wereimmersed in cyclopentanone for 120 seconds (composition Example 9A) and70 seconds (composition Example 9B) to reveal the lines (L), pillars (P)and holes (H). The photo imaging properties are summarized in Table 6.

TABLE 6 Composition FT Dose BFL Resolution Example No. μm mJ/cm² %L/P/H, μm Example 8A 5.40 1500 40% 15/20/20 Example 8B 6.19 765 18%15/15/40

Comparative Example 1 6FDA/6BF/BZXPh-5 (50/30/20)

A mixture of 6BF (15.13 g, 30 mmol) and BZXPh-5 (4.51 g, 20 mmol) wasdissolved in NMP (167.4 g) and stirred at ambient temperature under anitrogen atmosphere. To this solution was then added 6FDA (22.12 g, 50mmol) in small batches while stirring that generated about 5° C.exotherm. The reaction mixture was stirred at ambient temperature for 20hours. A small portion of this solution was diluted with DMAc for GPCanalysis. GPC-DMAc—M_(w)=174,300, M_(n)=85,600, PDI=2.04. A small sampleof the polymer solution was also added to excess water/acetone (80/20)mixture to isolate the polymer for ¹H NMR analysis. The gummy productwas washed with excess heptane and dried in a vacuum oven at 80-90° C.for 24 hours to obtain a solid product. ¹H-NMR (500 MHz) spectrameasured in deuterated DMSO showed a broad peak centered at about 13.5ppm for COOH and 10.96 ppm, 10.94 ppm, 10.86 ppm and 10.84 ppm for —NH—groups of the polyamic acid in approximately 1:1 ratio. Multiple peakswere observed at 6.7-8.4 ppm for the aromatic protons from 6FDA, BZXPh-5and 6BF.

The polyamic acid solution (100 g containing 20 g polymer) thus obtainedabove was mixed with anhydrous pyridine (25 g) and acetic anhydride (25g) and the solution heated to 90° C. for 4 hours under nitrogenatmosphere while stirring. The reaction mixture was allowed to cool toambient temperature and was added to excess water/acetone (80/20)mixture (1.5 L) to isolate the polymer. The gummy product was washedwith excess (1 L) heptanes and dried in a vacuum oven at 80-90° C. for24 hours to obtain a solid product (18.2 g, 92% isolated yield), whichwas characterized by GPC, ¹H NMR and FT-IR. GPC-DMAc—M_(w)=178,800,M_(n)=80,050, PDI=2.23. ¹H-NMR (500 MHz) spectra measured in deuteratedDMSO showed only traces of a broad peak centered at about 13 ppm forCOOH and 10-11 ppm for —NH— groups of the polyamic acid indicating thatthe polyamic acid was quantitatively imidized. Multiple peaks wereobserved at 6.7-8.6 ppm for the aromatic protons of 6FDA, 6BF andBZXPh-5. FT-IR spectra showed peaks at 1378 cm⁻¹ and 722 cm⁻¹characteristic of polyimides.

Although the invention has been illustrated by certain of the precedingexamples, it is not to be construed as being limited thereby; butrather, the invention encompasses the generic area as hereinbeforedisclosed. Various modifications and embodiments can be made withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. An end capped polyamic acid of the formula (IA)or an end capped polyimide of the formula (IB):

wherein: m is an integer of at least 50; X is one or more distincttetravalent organic group; Y is one or more distinct divalent organicgroup; and R₁ and R₂ are the same or different and each independently ofone another selected from the group consisting of linear or branched(C₁-C₁₆)alkenyl, hydroxy(C₁-C₁₂)alkenyl, perfluoro(C₁-C₁₂)alkenyl, and(C₆-C₁₀)aryl(C₁-C₃)alkenyl.
 2. The polyamic acid or polyimide accordingto claim 1, wherein X is derived from one or more dianhydrides selectedfrom the group consisting of:

1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA);

4-methyl-1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone;

5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA);

5,5′-(perfluoropentane-3,3-diyl)bis(isobenzofuran-1,3-dione);

5,5′-carbonylbis(isobenzofuran-1,3-dione) (BTDA);

5,5′-azanediylbis(isobenzofuran-1,3-dione);

[4,5′-biisobenzofuran]-1,1′,3,3′-tetraone (α-BPDA);

5,5′-oxybis(isobenzofuran-1,3-dione) (ODPA);

[5,5′-biisobenzofuran]-1,1′,3,3′-tetraone (BPDA); and

5-(2,5-dioxotetrahydrofuran-3-yl)-7-methyl-3a,4,5,7a-tetrahydroisobenzofuran-1,3-dione(D1901).
 3. The polyamic acid or polyimide according to claim 1, whereinY is derived from one or more diamines selected from the groupconsisting of:

4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF);

4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline(HFBAPP);

2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB);

4,4′-oxydianiline (4,4′-ODA);

4,4′-(1,3-phenylenebis(oxy))dianiline (APB);

4,4′-methylenebis(2,6-dimethylaniline) (DO3);

2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5);

2-(4-aminophenyl)benzo[d]oxazol-6-amine (BZXPh-6);

benzo[d]oxazole-2,5-diamine (BZX-5);

benzo[d]oxazole-2,6-diamine (BZX-6);

bicyclo[2.2.1]heptane-2,5-diyldimethanamine (NBDA); a diamine of formula(MA)

where, n=2 to 6 (JD-230);

4,4′-(perfluoropropane-2,2-diyl)bis(2-aminophenol) (BAFA); and

4,4′-(propane-2,2-diyl)bis(2-aminophenol) (DABPA).
 4. The polyamic acidor polyimide according to claim 1, wherein at least one end of the mainchain of the polyamic acid or the polyimide is end capped with acompound of formula (II):

wherein R₁ and R₂ are as defined in claim
 1. 5. The polyimide accordingto claim 4, wherein the compound of formula (II) is selected from thegroup consisting of:

itaconic anhydride (IA);

3-methyl-4-methylenedihydrofuran-2,5-dione;

3-(2-methylallyl)dihydrofuran-2,5-dione (MPSA); and

3-methyl-4-(2-methylallyl)dihydrofuran-2,5-dione.
 6. The polyimideaccording to claim 1, which is selected from the group consisting of: apolyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA); a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB) anditaconic anhydride (IA); a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline(HFBAPP), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB)and itaconic anhydride (IA); and a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA).
 7. The polyamic acid or polyimide according to claim 1having a weight average molecular weight (M_(w)) of at least 5,000 andis soluble in an organic solvent.
 8. The polyamic acid or polyimideaccording to claim 7, wherein the organic solvent is selected from thegroup consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL),N,N-dimethylacetamide (DMAc), propylene glycol monomethyl ether acetate(PGMEA), dimethyl sulfoxide (DMSO), cyclopentanone, cyclohexanone,2-butanone and 2-heptanone and mixtures in any combination thereof.
 9. Acomposition comprising: a) an end capped polyamic acid of the formula(IA) or an end capped polyimide of the formula (IB):

wherein: m is an integer of at least 50; X is one or more distincttetravalent organic group; Y is one or more distinct divalent organicgroup; and R₁ and R₂ are the same or different and each independently ofone another selected from the group consisting of linear or branched(C₁-C₁₆)alkenyl, hydroxy(C₁-C₁₂)alkenyl, perfluoro(C₁-C₁₂)alkenyl, and(C₆-C₁₀)aryl(C₁-C₃)alkenyl; b) a photo radical generator; and c) athermal radical generator.
 10. The composition according to claim 9,wherein the polyamic acid or polyimide is derived from one or moredianhydrides selected from the group consisting of:

1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA);

4-methyl-1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone;

5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA);

5,5′-(perfluoropentane-3,3-diyl)bis(isobenzofuran-1,3-dione);

5,5′-carbonylbis(isobenzofuran-1,3-dione) (BTDA);

5,5′-azanediylbis(isobenzofuran-1,3-dione);

[4,5′-biisobenzofuran]-1,1′,3,3′-tetraone (α-BPDA);

5,5′-oxybis(isobenzofuran-1,3-dione) (ODPA); and

[5,5′-biisobenzofuran]-1,1′,3,3′-tetraone (BPDA).
 11. The compositionaccording to claim 9, wherein the polyamic acid or the polyimide isderived from one or more diamines selected from the group consisting of:

4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF);

4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline(HFBAPP);

2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB);

4,4′-oxydianiline (4,4′-ODA);

4,4′-(1,3-phenylenebis(oxy))dianiline (APB);

4,4′-methylenebis(2,6-dimethylaniline) (DO3);

2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5);

2-(4-aminophenyl)benzo[d]oxazol-6-amine (BZXPh-6);

benzo[d]oxazole-2,5-diamine (BZX-5);

benzo[d]oxazole-2,6-diamine (BZX-6);

bicyclo[2.2.1]heptane-2,5-diyldimethanamine (NBDA); and a diamine offormula (III)

where, n=2 to 6 (JD-230).
 12. The composition according to claim 9,wherein at least one end of the main chain of the polyamic acid or thepolyimide is end capped with a compound of formula (II):

wherein R₁ and R₂ are as defined in claim
 9. 13. The compositionaccording to claim 9, wherein the polyimide is selected from the groupconsisting of: a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA); a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB) anditaconic anhydride (IA); a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))dianiline(HFBAPP), 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (PFMB)and itaconic anhydride (IA); and a polyimide formed from5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione) (6FDA),1H,3H-benzo[1,2-c:4,5-c′]difuran-1,3,5,7-tetraone (PMDA),4,4′-([1,1′-biphenyl]-4,4′-diylbis(oxy))bis(3-(trifluoromethyl)aniline)(6BF), 2-(4-aminophenyl)benzo[d]oxazol-5-amine (BZXPh-5) and itaconicanhydride (IA).
 14. The composition according to claim 9, wherein thephoto radical generator is selected from the group consisting of: acompound of formula (IV):

wherein R₆ and R₇ are the same or different and each independently ofone another selected from the group consisting of hydrogen, linear orbranched (C₁-C₈)alkyl and (C₆-C₁₀)aryl; or R₆ and R₇ taken together withthe nitrogen atom to which they are attached to form a 5 to 7 memberedmonocyclic ring or 6 to 12 membered bicyclic ring, said ring optionallycontaining one or more heteroatoms selected from 0 and N, and said ringoptionally substituted with linear or branched (C₁-C₈)alkyl,(C₆-C₁₀)aryl, halogen, hydroxy, linear or branched (C₁-C₈)alkoxy and(C₆-C₁₀)aryloxy; and R₈, R₉ and R₁₀ are the same or different and eachindependently of one another is selected from the group consisting ofhydrogen, linear or branched (C₁-C₁₆)alkyl, (C₆-C₁₀)aryl,(C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy, halogen, linear or branched(C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy; and a compound of formula (V):

wherein d is an integer from 0 to 3, inclusive; R₁₁ is selected from thegroup consisting of hydrogen, linear or branched (C₁-C₁₆)alkyl,(C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl, hydroxy, halogen, linear orbranched (C₁-C₁₂)alkoxy and (C₆-C₁₀)aryloxy; R₁₂ is selected from thegroup consisting of linear or branched (C₁-C₁₆)alkyl, (C₃-C₈)cycloalkyl,(C₆-C₁₀)aryl, (C₆-C₁₀)aryl(C₁-C₃)alkyl,(C₆-C₁₀)aryl(C₁-C₆)alkylphosphinate, (C₆-C₁₀)heterocycle(C₁-C₃)alkyl, agroup of formula C(O)—(OCH₂CH₂)_(c)—OC(O)C(O)(C₆-C₁₀)aryl, where e is aninteger from 2 to 4, inclusive, C(O)C(O)O(C₁-C₃)alkyl and a group offormula (C):

wherein R₁₃ is linear or branched (C₁-C₁₆)alkyl; and R₁₄ is(C₆-C₁₀)aryl; and where each of said alkyl, cycloalkyl, aryl andheterocycle may additionally be substituted with one or more groupsselected from the group consisting of hydroxy, linear or branched(C₁-C₆)alkyl, linear or branched (C₁-C₆)alkoxy and linear or branchedthio(C₁-C₆)alkyl.
 15. The composition according to claim 9, wherein thephoto radical generator is selected from the group consisting of:

(1-hydroxycyclohexyl)(phenyl)methanone;

2,2-dimethoxy-1,2-diphenylethan-1-one;

(phenylphosphoryl)bis(mesitylmethanone);

(diphenylphosphoryl)(mesityl)methanone;

ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate;

(diphenylphosphoryl)(mesityl)methanone;

2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one;

2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one;

oxybis(ethane-2,1-diyl) bis(2-oxo-2-phenylacetate);

(E)-2-((benzoyloxy)imino)-1-(4-(phenylthio)phenyl)octan-1-one;

methyl 2-oxo-2-phenylacetate;

benzophenone;

2-hydroxy-2-methyl-1-phenylpropan-1-one;

2-hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropan-1-one;

2,2-dimethyl-1-phenylpropan-1-one; and a mixture in any combinationthereof.
 16. The composition according to claim 9, wherein the thermalradical generator is selected from the group consisting of: benzoylperoxide, dicumyl peroxide, m-chloroperbenzoic acid, methyl ethyl ketoneperoxide, azobisisobutyronitrile (AIBN),(1-phenyl-3,3-dipropyltriazene), (1-(phenyldiazenyl)pyrrolidine),(1-(phenyldiazenyl)piperidine) and (1-(phenyldiazenyl)azepane).
 17. Thecomposition according to claim 9, further comprising one or morephotosensitizers selected from the group consisting of:

1-chloro-4-methoxy-9H-thioxanthen-9-one;

1-chloro-4-ethoxy-9H-thioxanthen-9-one;

1-chloro-4-propoxy-9H-thioxanthen-9-one;

1-chloro-2-propoxy-9H-thioxanthen-9-one;

1-chloro-2-ethoxy-9H-thioxanthen-9-one;

1-chloro-2-methoxy-9H-thioxanthen-9-one;

1-chloro-4-methyl-9H-thioxanthen-9-one;

1-chloro-4-ethyl-9H-thioxanthen-9-one;

1-bromo-4-propoxy-9H-thioxanthen-9-one;

1-chloro-4-phenoxy-9H-thioxanthen-9-one;

2,4-diethyl-9H-thioxanthen-9-one; and

2-isopropyl-9H-thioxanthen-9-one.
 18. The composition according to claim9, further comprising one or more crosslinking agents selected from thegroup consisting of:

(2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)tris(ethane-2,1-diyl)triacrylate (TAEICY);

(oxybis(methylene))bis(2-ethylpropane-2,1,3-triyl) tetraacrylate(BTMPTA);

2,2′-(((2-ethyl-2-((oxiran-2-ylmethoxy)methyl)propane-1,3-diyl)bis(oxy))bis(methylene))bis(oxirane)(TMPTGE);

2,2-bis(((3-mercaptopropanoyl)oxy)methyl)propane-1,3-diylbis(3-mercaptopropanoate) (PET3MP); and

2,2,2′,2′-tetrakis(3-mercaptopropanoyl)-3,3′(3-mercaptopropanoyl)-1,1′-dipropylether (DPEH3MP).
 19. A cured product comprising the composition of claim9.
 20. A microelectronic or optoelectronic device comprising one or moreof a redistribution layer (RDL) structure, a chip-stack structure, aCMOS image sensor dam structure, where said structures comprising acomposition according to claim 9.